From: Gupta, Gopal (NWCC) (gopal.gupta@hp.com)
Date: Fri Nov 23 2007 - 13:58:33 ART
Thanks to all of you guys, There is no more confusion now.
________________________________
From: Narbik Kocharians [mailto:narbikk@gmail.com]
Sent: Friday, November 23, 2007 22:04
To: Gupta, Gopal (NWCC)
Cc: Joel Amao; Cisco certification
Subject: Re: BGP Next-Hop
Therefore no need to set the next hop
On 11/23/07, Narbik Kocharians <narbikk@gmail.com> wrote:
The assumption here is that on a given multiaccess networks,
every host has reachability to every other host.
On 11/23/07, Narbik Kocharians <narbikk@gmail.com > wrote:
You can resolve it via a route-map configured on the
spokes, they can match on the AS number of the other spoke and set the
ip next-hop to the hub, but this needs to be done on both spokes.
On 11/23/07, Gupta, Gopal (NWCC) <gopal.gupta@hp.com >
wrote:
Thanks for your inputs,
Till here its fine, but i would like to know why
we cant we use neighbor
x.x.x.x next-hop-self command in this case, why
to set next-hop
manually; this is waht my concern is.
Thanks
Gops
________________________________
From: Joel Amao [mailto: femmy79@hotmail.com
<mailto:femmy79@hotmail.com> ]
Sent: Friday, November 23, 2007 21:14
To: Gupta, Gopal (NWCC); Cisco certification
Subject: RE: BGP Next-Hop
Hello Gupta,
what you are seeing is normal and expected.
There is an exception to egbg next hop
modification in broadcast and
NBMA mode called third-party next hop
modification.
The normal rule regarding next-hop modification
is below;
1. If the route is locally originated set the
NEXT-HOP to the peering
ip address (even if sent to an IBGP peer)
2. If the route is propagated to an eBGP peer,
set the NEXT-HOP to our
peering ip address
3. If the route is propagated to an iBGP peer,
do not change the
NEXT-HOP
**exception to this rule **When two peers are in
a multiaccess network
(Frame Relay multipoint interface, Ethernet,
etc) we dont change the
next-hop.
thanks,
Joel Amao
CCIE#18128
> Subject: BGP Next-Hop
> Date: Fri, 23 Nov 2007 19:33:56 +0530
> From: gopal.gupta@hp.com
> To: ccielab@groupstudy.com
>
> Hi Folks,
>
> I am facing issue with BGP..
>
> R1 , R2, R3 are spokes connected to hub R5
throgh Frame relay .... all
> with the major interface.
> having subnet 155.1.0.0/24 and all are in
their own individual AS ; R1
> is in AS1, R2 in 2, R3 in 3, R5 in 5.
>
> when routes originated by R2 are sent to R5
and then R5 in turn sends
> that route to R3 or R1, the next hop doesn't
change which should be
> changed coz of EBGP connections and should not
be changed coz of
> Frame-relay NBMA on same subnet.
>
> and if i try to set next-hop-self under
neighbor stement on R5 for
> R1,R2&R3..i get an error message
>
> R5(config-router)#neighbor 155.1.0.1
<http://155.1.0.1/> next-hop-self
> %BGP: next-hop-self is implied for an eBGP
peer, there is no need to
> configure it
> R5(config-router)#neighbor 155.1.0.2
<http://155.1.0.2/> next-hop-self
> %BGP: next-hop-self is implied for an eBGP
peer, there is no need to
> configure it
> R5(config-router)#neighbor 155.1.0.3
<http://155.1.0.3/> next-hop-self
> %BGP: next-hop-self is implied for an eBGP
peer, there is no need to
> configure it
>
> I know i can set it manually throgh Route-map,
is this the only way we
> can have workaround or i am missing
something.....not sure.
>
> Any Comments please !!!!!!
>
> Best Regards,
> Gops
>
>
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